The present invention relates to polyethylene fabrics with improved physical properties. In particular, the present invention relates to improved polyethylene fabric for use in applications where a consistent amount of stretch under a fixed load with varying temperatures is important. Specific examples include tensioned fabric buildings and lay flat irrigation hose.
Polyethylene fabrics have many advantages. Such fabrics are lightweight, non-toxic and can be recycled for other uses. They can exist and be used in both woven and non-woven form. Further, polyethylene fabric can be woven into sheets and used in a variety of applications to make hoses for a variety of applications such as irrigation, and general water delivery in such industries as mining, agriculture, construction, fluming and greenhouse uses. In products used for these applications, polyethylene comprises and important part of the end product.
A disadvantage of conventional high density polyethylene fabric (HDPE) is that stretching occurs when HDPE is placed under stress. This stretching increases as temperature increases. Thus in high temperature, high stress environments, HDPE fabrics may not exhibit the dimensional integrity needed for that application.
However, polyethylene products in general and high density polyethylene products (HDPE) in particular, when used to provide reinforcing scrims, have a lower capacity to hold stress without stretching as the temperature is increased. In irrigation applications, the tube or hose may burst under pressure at higher temperatures. In one example, a tube or hose of about 3 inches in diameter can hold 400 kPa at room temperature with only a small amount of stretch. However, when the temperature is increased to 60 C (degrees Centigrade), the tube stretches significantly thereby endangering its structural integrity. This stretching of the reinforcing scrim allows any coating to stretch to the point that water flows through the material of the tube where/when it is not intended.
What would therefore be useful is an improved polyethylene fabric that resists stretching when under pressure and which maintains its structural integrity as temperature increases.